Programmable Shunt Valve Assembly for Stable Magnetic Pressure Setting
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Solution Overview
Problem
Existing magnetically adjustable shunts for hydrocephalus treatment are prone to pressure setting changes in strong magnetic fields, require invasive verification methods, and have bulky programmers that are not portable or battery-operated.
Innovation Solution
A surgically-implantable shunt valve assembly with a magnetically operable motor and a programmer device that includes a housing, motor, and magnet assembly, allowing for external adjustment of the valve's pressure setting using a portable, battery-operated system resistant to non-programming magnetic fields, and enabling pressure verification without X-rays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a magnetic valve assembly is used to allow external adjustment of pressure setting, then the ease of operation is improved, but the reliability deteriorates due to pressure setting changes in strong magnetic fields
Solution Approach 1:
A magnetic encoder disk with radial magnets serves as an intermediary between the rotor position and the external programmer. The encoder disk rotates with the rotor but its magnetic field is read by a stationary magnetic sensor, creating a reliable position signal that is not directly affected by external magnetic fields affecting the motor operation.
Solution Approach 2:
The patent replaces purely magnetic actuation with a hybrid system that includes a magnetic motor for actuation but uses a magnetic encoder system (combining magnetic field generation with magnetic sensing) for position feedback. This substitution of a purely magnetic system with one incorporating magnetic encoding provides reliability against external magnetic interference.
2Measurement precision
If radiopaque markers are used for pressure verification, then the measurement precision is improved, but the ease of operation deteriorates due to requirement of X-ray imaging
Solution Approach 1:
The patent replaces the radiopaque marker system (requiring X-ray imaging) with a magnetic encoder system that provides direct electronic position sensing. The magnetic sensor reads the position of the encoder disk through the housing wall, eliminating the need for invasive X-ray verification while maintaining measurement precision.
Solution Approach 2:
The magnetic encoder disk acts as an intermediary that translates mechanical rotor position into a magnetic signal that can be read by the stationary magnetic sensor. This intermediary system provides non-invasive, direct verification of pressure settings without requiring external imaging equipment.
3Ease of operation
If a traditional programmer design is used, then the ease of operation is improved for pressure adjustment, but the weight and portability deteriorate
Solution Approach 1:
The patent extracts the heavy electromagnet components from the programmer device, retaining only the essential magnetic field generation capability through a simplified magnet assembly. This extraction of unnecessary mass (electromagnet power supplies, cooling systems, etc.) while preserving the core magnetic actuation function reduces weight and improves portability.
Solution Approach 2:
The patent employs a simplified magnet assembly that may be less durable than traditional electromagnet systems but is sufficient for the intended use. This approach prioritizes portability and cost-effectiveness over long-term durability, accepting that the lighter magnet assembly may have limitations in extreme conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a reliable, portable, and non-invasive method to adjust and verify the pressure setting of the shunt valve, maintaining accuracy even in strong magnetic fields and improving the convenience and safety of the treatment process.
Implementation Method 1
a magnet assembly coupled to the motor and configured to rotate with respect to the housing, the magnet assembly including at least one permanent magnet to apply the external magnetic field on the valve assembly
Implementation Method 2
a motor coupled to the housing, and a magnet assembly coupled to the motor and configured to rotate with respect to the housing
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An externally programmable shunt valve assembly that includes a motor having a rotor that is operable in response to an externally applied magnetic field and configured to increase or decrease the working pressure of the shunt valve assembly. The motor may further include a position sensing mechanism that allows a position of the rotor, and associated pressure setting of the valve, to be determined using an external magnetic sensor. In certain examples the motor further includes a mechanical brake that is magnetically operable between a locked position and an unlocked position and which, in the locked position, prevents rotation of the rotor.